Nearly half of U.S. children 'undervaccinated,' study finds

Results of a newly-released study highlights a growing number of U.S. parents are opting not to have their children vaccinated according to health guidelines.

The study from the Kaiser Permanente Colorado Institute for Health Research found that nearly half of young people between the ages of 2 and 24 have either not followed the recommended vaccination schedule, or have not been vaccinated at all.

Common objections to following the recommended vaccine regime include concerns over the number of vaccinations, the age at which vaccinations start and a belief that other precautions or treatments would be better.

Based on her experience, CTV medical consultant Dr. Marla Shapiro believes the same trend has taken hold in Canada, too.

Many parents overwhelmed by long-held misconceptions further fuelled by the online chatter of social media are opting out, Shapiro said.

"There's this fear that's not based on evidence, or science," Shapiro told CTV News Channel, suggesting that anyone who delves into the facts about vaccines would find no reason to fear them.

And the consequence of skipping immunizations can be grave, she said.

Anyone who declines the vaccine for chicken pox, for example, might think they're only risking coming down with a highly contagious, albeit non-life-threatening illness.

But the reality, in Shapiro's view, is they risk coming down with one of the many more perilous complications of the disease.

"You can have... widespread complications that are not as common, but if they happen with a vaccine-preventable illness, it's just heartbreaking to see," she said. "I think we're getting complacent, and we're not relying on the science or the evidence."